adj. & n.
--adj. occurring or done unexpectedly or without warning; abrupt, hurried, hasty (a sudden storm; a sudden departure).
--n. archaic a hasty or abrupt occurrence.
Phrases and idioms:
all of a sudden unexpectedly; hurriedly; suddenly. on a sudden archaic suddenly. sudden death colloq. a decision in a tied game etc. dependent on one move, card, toss of a coin, etc. sudden infant death syndrome Med. cot-death (see COT(1)).
Derivatives:
suddenly adv. suddenness n.
Etymology: ME f. AF sodein, sudein, OF soudain f. LL subitanus f. L subitaneus f. subitus sudden